Implant and delivery system for neural stimulator

ABSTRACT

Apparatus is provided for use with an optical fiber shape-sensing system. The apparatus includes an optical fiber, optically couplable to the optical fiber shape-sensing system, and configured to change shape during advancement through a greater palatine canal of a subject. The apparatus additionally includes a delivery tool configured to be removably coupled to the optical fiber and to distally advance the optical fiber through the greater palatine canal. The apparatus further includes a neural stimulator implant, configured to apply electrical stimulation to a sphenopalatine ganglion (SPG) of the subject. The neural stimulator implant is not in contact with the optical fiber, and is shaped and sized to be delivered to the sphenopalatine ganglion (SPG) by the delivery tool. Other applications are also described.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority from:

U.S. Provisional Application 62/160,708 to Dayan et al., entitled“Implant and delivery system for neural stimulator,” filed May 13, 2015.

The present application is related to:

(a) U.S. application Ser. No. 14/536,924 to Dayan et al., entitled“Implant and delivery system for neural stimulator,” filed Nov. 10,2014, now U.S. Pat. No. 9,675,796;

(b) EP Application 14192536.2 to Dayan et al., entitled “Implant anddelivery system for neural stimulator,” filed Nov. 10, 2014 andpublished as EP2878335; and

(c) Israel Patent Application No. 229345 to Dayan et al., entitled“Implant and delivery system for neural stimulator,” filed Nov. 10,2013; and

(d) EP Application 14192536.2 to Dayan et al., filed Nov. 10, 2014,entitled “Implant and delivery system for neural stimulator,”

each of which is incorporated herein by reference.

FIELD OF THE APPLICATION

Some applications of the invention relate generally to medicalprocedures and implantable devices. More specifically, some applicationsof the invention relate to the use of electrical devices forimplantation in the head.

BACKGROUND

Surgical guides are typically generated based on computed tomography(CT) image data, and provide a dentist with guidance as to an optimallocation for drilling into a jaw bone of a subject during implantationof dental implants.

U.S. Pat. No. 7,120,489 to Shalev and Gross, which is assigned to theassignee of the present patent application and is incorporated herein byreference, describes apparatus for modifying a property of a brain of apatient, including electrodes applied to a sphenopalatine ganglion (SPG)or a neural tract originating in or leading to the SPG. A control unitdrives the electrodes to apply a current capable of inducing (a) anincrease in permeability of a blood-brain barrier (BBB) of the patient,(b) a change in cerebral blood flow of the patient, and/or (c) aninhibition of parasympathetic activity of the SPG.

U.S. Pat. No. 7,117,033 to Shalev et al., describes a method fortreating a subject, comprising positioning at least one electrode atleast one site of the subject for less than about 3 hours, applying anelectrical current to the site of the subject, and configuring thecurrent to increase cerebral blood flow (CBF) of the subject, so as totreat a condition of the subject. The site is selected from the listconsisting of: a sphenopalatine ganglion (SPG) of the subject, a greaterpalatine nerve of the subject, a lesser palatine nerve of the subject, asphenopalatine nerve of the subject, a communicating branch between amaxillary nerve and an SPG of the subject, an otic ganglion of thesubject, an afferent fiber going into the otic ganglion of the subject,an efferent fiber going out of the otic ganglion of the subject, aninfraorbital nerve of the subject, a vidian nerve of the subject, agreater superficial petrosal nerve of the subject, and a lesser deeppetrosal nerve of the subject.

U.S. Pat. No. 7,561,919 to Shalev et al., describes apparatus forapplication to a subject, including an elongated support element havinga length of between 1.8 cm and 4 cm, and having proximal and distalends; and one or more electrodes fixed to the support element in avicinity of the distal end thereof, and adapted to apply an electricalcurrent to a sphenopalatine ganglion (SPG) of the subject. The apparatusfurther includes a receiver, fixed to the support element, andelectrically coupled to the electrodes; and a wireless transmitter,adapted to be placed in an oral cavity of the subject, and to bewirelessly coupled to the receiver. Other embodiments are alsodescribed.

U.S. Pat. No. 7,772,541 to Froggatt et al., and US Patent ApplicationPublication 2006-0013523 to Childlers et al., are each incorporatedherein by reference.

SUMMARY OF APPLICATIONS

In some applications, a system is provided for delivery of a neuralstimulator implant for electrical stimulation of a sphenopalatineganglion (SPG) of a subject. Stimulation of the SPG typically treatsvarious acute brain hypoperfusion states, such as occur during acuteischemic stroke. Typically, the system includes apparatus comprising animplantable neural stimulator, a steerable delivery guide, and an oralsurgical guide.

The neural stimulator implant is configured to be passed through agreater palatine foramen of a palate of an oral cavity of a subject intoa greater palatine canal, such that the neural stimulator implant isbrought into a vicinity of a sphenopalatine ganglion (SPG), for example,into contact with the SPG. For some applications, the implant is aflexible implant configured to conform to the anatomical structure ofthe greater palatine canal, to facilitate advancement therethrough. Forsome applications, the implant comprises at least one electrode forstimulation of the SPG.

The neural stimulator implant is typically coupled to the steerabledelivery guide. For some applications, a distal end of the steerabledelivery guide is configured to puncture oral mucosa of the subject,allowing the neural stimulator implant to be passed through the palatein a minimally-invasive procedure, without requiring a prior surgicalincision in the mucosa. Typically, the distal end of the steerabledelivery guide is also configured to be passed through the greaterpalatine foramen into the greater palatine canal. The delivery guide issteered in the canal in order to deliver the neural stimulator implantto the SPG.

Typically, the surgical guide is generated based on CT data obtained byimaging the subject. Based on the CT data, the surgical guide is formedto provide a guide hole for locating the entrance to the greaterpalatine canal, such that the implantable neural stimulator may bepassed through the guide hole and then into the greater palatine canal.In particular, the surgical guide is typically configured for placementon the subject's dental arch, such that an extension portion of thesurgical guide extending away from the dental arch contacts the roof ofthe oral cavity of the subject, and the guide hole is therebyautomatically placed over the entrance to the greater palatine foramenof the subject.

For some applications, the surgical guide is generated based on datafrom both a CT scan and an intra-oral scan. For such applications, anintra-oral scan of the upper palate, teeth, and/or gums of the subjectis performed in addition to the CT scan, and the data from both scansare registered for preparation of the surgical guide. Alternatively, thesurgical guide is initially generated based on data from an intra-oralscan only, and subsequently CT data are used for preparing the guidehole in the surgical guide.

Thus, in accordance with some applications of the present invention, thesurgical guide is configured to guide an operating physician to thelocation of the greater palatine foramen of the subject, to facilitateadvancement of the neural stimulator implant therethrough by injectingthe implant into the canal. Additionally, the guide hole in the surgicalguide facilitates penetration of the mucosa at an appropriate angle forentrance into the greater palatine foramen at an angle suitable foradvancement of the neural stimulator implant through the canal. Furtheradditionally, the CT data in combination with the surgical guideprovides the operating physician with information regarding theanatomical structure of the greater palatine canal, thereby facilitatingnavigation and advancement of the implantable neural stimulator coupledto the steerable delivery guide through the canal. Thus, in accordancewith some applications, the surgical guide in combination with the CTdata, guides the passing through oral mucosa of the subject andnavigation of the neural stimulator implant within a complex anatomicalstructure. Additionally, but not necessarily, the surgical guideprovides guidance for drilling at a predetermined depth into the jawbone.

The surgical guide typically allows for use of the neural stimulatorimplant by facilitating precise and safe implant deployment at the SPG,even by a less-skilled surgeon. Similarly, in general, the surgicalguide allows a less-skilled surgeon to access the SPG in a safe andprecise manner (even in the absence of implanting a neural stimulatorimplant).

For some applications, the delivery guide is configured to facilitatedelivery of the neural stimulator to the SPG site without the need forthe physician to consider a navigation map of the greater palatinecanal. For some such applications, CT data regarding the anatomicalstructure of the greater palatine canal is used to create (typically by3D printing) a curved guide groove surface on a portion of the deliveryguide. When the neural stimulator is mounted on a distal end of thedelivery guide, it is advanced distally in the canal by advancement of aslide-bar of the delivery guide. At the same time, a guiding pin whichis disposed within the curved guide groove is advanced within thegroove, causing rotation of the slide-bar with respect to the deliveryguide, thereby steering the neural stimulator in the greater palatinecanal.

For some applications, a shape-sensing optical fiber optically couplableto an optical fiber shape-sensing system is provided. The shape-sensingoptical fiber typically is advanced by a delivery tool, e.g., a trocar,through the palatine canal and a shape of the canal is assessed usingthe shape-sensing optical fiber. The shape-sensing optical fiber is thenremoved from the canal. Subsequently, the neural stimulator implant isadvanced and navigated through the palatine canal based on the assessingof the shape of the canal by the shape-sensing optical fiber.

For other applications, the neural stimulator implant additionallycomprises the shape-sensing optical fiber optically couplable to anoptical fiber shape-sensing system. The shape-sensing optical fiber isconfigured to change shape during delivery of the implant to the SPGthrough the greater palatine canal, to facilitate advancement andnavigation of the implant through the canal.

There is therefore provided, in accordance with an application of thepresent invention, apparatus, including:

-   -   an oral surgical guide including:    -   an arch portion configured to be placed on a dental arch of a        subject; and    -   an extension portion extending from the arch portion, and shaped        to define a guide hole.

For some applications, the extension portion extends from the archportion in a superior and lingual direction with respect to the arch.

For some applications, the apparatus includes:

-   -   a steerable implantable neural stimulator configured to apply        electrical stimulation to a sphenopalatine ganglion (SPG) of the        subject,    -   the guide hole is configured to guide the stimulator through a        greater palatine foramen of a palate of an oral cavity of the        subject and into a greater palatine canal of the subject.

For some applications, the guide hole is configured to guide thestimulator through the greater palatine foramen at an angle that issuitable for entering the greater palatine canal.

For some applications, the surgical guide is generated by using CT scandata of the subject and intra-oral scan data of the subject, and theguide hole corresponds to a location of a greater palatine foramen ofthe subject.

For some applications, a portion of the surgical guide corresponding toa surface of gum tissue of the subject is shaped in a curved manner thatmatches curvature of the gum tissue.

For some applications, the surgical guide is generated by using CT scandata of the subject and not using intra-oral scan data of the subject,and the guide hole corresponds to a location of a greater palatineforamen of the subject.

For some applications, the implant is shaped to define proximal anddistal portions, and the distal portion of the implant is configured topuncture oral mucosa of the subject.

For some applications, the implant is shaped to define proximal anddistal portions, and the distal portion of the implant includes at leastone electrode configured to apply electrical stimulation to asphenopalatine ganglion (SPG) of the subject.

For some applications, the surgical guide is formed by athree-dimensional printing process.

For some applications, the surgical guide is shaped by shaping a pliablematerial on the dental arch of the subject.

For some applications, the pliable material includes a thermoplasticmaterial.

There is further provided, in accordance with an application of thepresent invention, a method including:

using an oral surgical guide generated using CT data to determine alocation of a greater palatine foramen of a palate of an oral cavity ofa subject;

inserting a steerable implantable neural stimulator into the greaterpalatine foramen of the subject, through a hole in the surgical guide;and advancing the stimulator through a greater palatine canal of thesubject to a sphenopalatine ganglion (SPG) of the subject.

For some applications, using the oral surgical guide generated using CTdata further includes using the oral surgical guide to determine asuitable angle for entering of the greater palatine canal, and insertingthe stimulator into the greater palatine foramen includes inserting thestimulator at the suitable angle.

For some applications, the method includes creating an opening in mucosaof the subject using the stimulator, and inserting the stimulatorincludes stimulator through the opening.

For some applications, the method includes coupling a tool, in which thestimulator is disposed, to the hole in the surgical guide, and creatingthe opening includes creating the opening while the tool is coupled tothe hole in the surgical guide.

For some applications, inserting the stimulator includes inserting thestimulator using a tool, and the method further includes, following theadvancing of the stimulator, allowing the tool to be withdrawn from thegreater palatine canal without dislodging the stimulator by disengaginga locking element of the stimulator from the tool.

For some applications, the locking element is shaped as a ball, anddisengaging the locking element includes disengaging the ball-shapedlocking element from the tool.

There is further provided, in accordance with an application of thepresent invention, apparatus for use with a tool, the apparatusincluding:

an oral surgical guide including:

-   -   an arch portion configured to be placed on a dental arch of a        subject; and    -   an extension portion from the arch portion, and shaped to        define (a) a guide hole, and (b) a protruding portion including        a first coupling element configured to lockingly couple to the        tool.

For some applications, the protruding portion is shaped to define ascrew thread.

There is further provided, in accordance with an application of thepresent invention, a method including:

using a processor, receiving CT data of an oral cavity of a subjectacquired while (a) a surgical guide and (b) one or more markers, were inthe oral cavity;

using the processor, identifying a position of one or more markers on adrill with respect to respective sites on the surgical guidecorresponding to the markers in the oral cavity; and

using the processor and the identified position, guiding drilling of ahole in the surgical guide, by the drill, at a site on the surgicalguide corresponding to a greater palatine foramen of the subject.

For some applications, the one or more markers are on the surgicalguide, and receiving the CT data using the processor includes receivingthe CT data using the processor, the CT data having been acquired whilethe surgical guide having the one or more markers thereon was in theoral cavity.

For some applications, the one or more markers in the oral cavity areone or more teeth of the subject.

For some applications, the surgical guide includes a thermoplasticmaterial and guiding drilling of a hole in the surgical guide includesdrilling a hole in the thermoplastic material.

There is further provided, in accordance with an application of thepresent invention, a method, including:

providing a flexible, elongate implant having electrodes thereon and anunconstrained shape having a bend at least at a distal end portion ofthe implant;

subsequently, advancing the implant through a greater palatine canal ofa subject; and

utilizing the bend at the distal end portion of the implant tofacilitate steering of the implant during the advancing of the implant.

For some applications, the implant includes a nitinol portion whichprovides the bend, and providing the implant includes providing theimplant having the nitinol portion.

For some applications, the method includes, following the advancing ofthe implant, leaving the implant in the greater palatine canal of thesubject while the distal end portion of the implant is constrained andnot bent as it was prior to the advancing of the implant.

There is further provided, in accordance with an application of thepresent invention, apparatus, including:

a flexible, elongate implant, the implant having an unconstrained shapehaving a bend at least at a distal end portion of the implant, theimplant including:

-   -   two or more electrodes;    -   a flexible portion disposed at least between the two electrodes;        and    -   a receiving coil configured to receive energy for powering        driving of the electrodes.

There is further provided, in accordance with an application of thepresent invention, apparatus including:

an elongated implantable neural stimulator having proximal and distalsites and configured to apply electrical stimulation to a sphenopalatineganglion (SPG) of a subject; and

electronic circuitry having first and second portions and coupledrespectively to the proximal and distal sites of the implantable neuralstimulator, the electronic circuitry in the first portion being flexiblycoupled to the electronic circuitry in the second portion.

For some applications, the apparatus includes a flexible connectingelement coupled to the first and second portions of the electroniccircuitry.

There is further provided, in accordance with an application of thepresent invention, apparatus for delivery of an implantable neuralstimulator to a sphenopalatine ganglion (SPG) of a subject, including:

a tool having a distal portion coupled to the implantable neuralstimulator and a proximal portion; and

a slide-bar at the proximal portion of the tool, the slide-bar includinga distal portion and a proximal portion, the proximal portion of theslide-bar being coupled to the stimulator such that distal advancementof the proximal portion of the slide-bar produces distal advancement ofthe stimulator, the proximal and distal portions of the slide-bar eachincluding a respective magnetic element, the magnetic elements beingconfigured to couple the proximal and distal portions of the slide-barto each other unless a distally-directed force applied to the distalportion of the slide-bar exceeds a threshold.

There is yet further provided, in accordance with an application of thepresent invention, a method including:

using an oral surgical guide generated using scan data selected from thegroup consisting of: intra-oral scan data and CT scan data, to determinea location of a greater palatine foramen of a palate of an oral cavityof a subject;

inserting a steerable implantable neural stimulator into the greaterpalatine foramen of the subject, through a hole in the surgical guide;and

advancing the stimulator through a greater palatine canal of the subjectto a sphenopalatine ganglion (SPG) of the subject.

For some applications, using scan data selected from the groupconsisting of intra-oral scan data and CT scan data, includes using CTscan data and not intra-oral scan data.

For some applications, using scan data selected from the groupconsisting of intra-oral scan data and CT scan data, includes usingintra-oral scan data and not CT scan data.

For some applications, using scan data selected from the groupconsisting of intra-oral scan data and CT scan data, includes usingintra-oral scan data and CT scan data.

For some applications, using the oral surgical guide generated using thescan data includes using the oral surgical guide generated using the CTscan data, and using the oral surgical guide generated using the CT scandata further includes using the oral surgical guide to determine asuitable angle for entering of the greater palatine canal, and insertingthe stimulator into the greater palatine foramen includes inserting thestimulator at the suitable angle.

For some applications, the method includes creating an opening in mucosaof the subject using the stimulator, inserting the stimulator includesinserting the stimulator through the opening.

For some applications, the method includes coupling a tool, in which thestimulator is disposed, to the hole in the surgical guide, and creatingthe opening includes creating the opening while the tool is coupled tothe hole in the surgical guide.

For some applications, inserting the stimulator includes inserting thestimulator using a tool, and the method further includes, following theadvancing of the stimulator, allowing the tool to be withdrawn from thegreater palatine canal without dislodging the stimulator by disengaginga locking element of the stimulator from the tool.

For some applications, the locking element is shaped as a ball, anddisengaging the locking element includes disengaging the ball-shapedlocking element from the tool.

There is yet further provided, in accordance with an application of thepresent invention, a method including:

receiving CT scan data and intra-oral scan data of a subject; and

using the CT and intra-oral scan data, generating an oral surgical guideshaped to define a hole, the hole being placeable against a location ofa greater palatine foramen of the subject.

For some applications, generating the oral surgical guide includes:

generating the oral surgical guide without the hole, using theintra-oral scan data;

subsequently, performing the step of receiving the CT scan data; and

subsequently, generating the oral surgical guide with the hole bycreating the hole using the CT scan data.

There is yet further provided, in accordance with an application of thepresent invention, apparatus for delivery of an implant to an anatomicalsite of a subject, the apparatus including:

a delivery tool having a proximal portion, and having a distal portionthat is coupled to the implant;

a surface at the proximal portion, the surface shaped to define a curvedguide groove based on data obtained by imaging the anatomical site ofthe subject;

a slide-bar slidably coupled to the proximal portion; and

a guiding pin disposed within the curved guide groove and configuredsuch that distal advancement of the slide-bar with respect to theproximal portion produces (1) relative motion of the guiding pin withrespect to the curved guide groove, and (2) rotation of the slide-barwith respect to a longitudinal axis of the delivery tool.

For some applications, the surface shaped to define the curved guidegroove is a surface of the delivery tool, and the guiding pin is fixedlycoupled to the slide-bar.

For some applications, the surface shaped to define the curved guidegroove is a surface of the slide-bar, and the guiding pin is fixedlycoupled to the delivery tool.

There is still provided, in accordance with an application of thepresent invention, a system including:

a CT scanning device configured to image a subject;

an intra-oral scanning device configured to image the subject; and athree-dimensional printing device configured to generate, based on theCT and intra-oral scanning of the subject, a surgical guide that isshaped to define a guide hole for locating a greater palatine foramen ofa palate of an oral cavity of the subject.

There is further provided, in accordance with an application of thepresent invention, apparatus for use with an optical fiber shape-sensingsystem, the apparatus including:

an implant including (a) a neural stimulator configured to applyelectrical stimulation to a sphenopalatine ganglion (SPG) of a subject,and (b) an optical fiber fixed to the neural stimulator, opticallycouplable to the optical fiber shape-sensing system, and configured tochange shape during delivery of the implant to the SPG through a greaterpalatine canal of the subject; and

a delivery tool configured (a) to be removably coupled to the implant,(b) to deliver the implant to the SPG through the greater palatinecanal, and (c) to detach from the implant once the implant is deliveredto the SPG.

For some applications, the optical fiber shape-sensing system includesoptical fiber shape-sensing circuitry and the optical fiber is opticallycouplable to the optical fiber shape-sensing circuitry.

For some applications, the delivery tool includes a detachment mechanismconfigured to detach the delivery tool from the implant.

For some applications, the detachment mechanism includes a cutting tool,and the cutting tool is configured to cut the optical fiber.

For some applications, the detachment mechanism includes a cutting tool,and the detachment mechanism is configured to detach the delivery toolfrom the implant by cutting the optical fiber.

For some applications, a portion of the optical fiber (a) is disposed inthe delivery tool, and (b) is shaped within the delivery tool such thatrelative motion between the implant and the delivery tool causes achange in the shape of the portion of the optical fiber.

For some applications, the portion of the optical fiber in the deliverytool is shaped to define a loop, such that distancing of the deliverytool from the implant causes a reduction in a diameter of the loop.

For some applications, the portion of the optical fiber in the deliverytool is shaped to define a curve, such that distancing of the deliverytool from the implant causes a straightening of the curve.

For some applications the apparatus further includes, a proximity sensorconfigured to indicate that the delivery tool is detached from theimplant by generating a signal that varies in response to relativemotion between the delivery tool and the implant.

For some applications, the proximity sensor includes at least oneradiofrequency (RF) coil coupled to the implant and at least one RF coilcoupled to the delivery tool.

For some applications, the proximity sensor includes at least onemagnetic element coupled to the implant and at least one magneticelement coupled to the delivery tool.

For some applications, the neural stimulator has a proximal portion, adistal portion and a middle portion between the proximal and distalportions, and the proximal portion is more rigid than the middleportion.

For some applications, the distal portion is more rigid than the middleportion.

There is further provided in accordance with an application of thepresent invention, a method including:

using a delivery tool, distally advancing, through a greater palatinecanal of a subject, an optical fiber and a neural stimulator that isconfigured to apply electrical stimulation to a sphenopalatine ganglion(SPG) of the subject, the optical fiber being configured to change shapeduring advancement of the neural stimulator through the greater palatinecanal; and

assessing a shape of the palatine canal using an optical fibershape-sensing system, based on a shape of the optical fiber duringadvancement.

For some applications, the optical fiber is coupled to the neuralstimulator, and distally advancing includes distally advancing theoptical fiber coupled to the neural stimulator.

For some applications, the optical fiber is coupled to the deliverytool, and distally advancing includes distally advancing the opticalfiber coupled to the delivery tool.

For some applications, the optical fiber contacts the neural stimulatorduring the step of distal advancing using the delivery tool.

For some applications, the optical fiber is wrapped around a portion ofthe neural stimulator during the step of distal advancing using thedelivery tool.

For some applications, the method includes:

deploying the neural stimulator in a vicinity of the SPG; and

decoupling the optical fiber from the neural stimulator by pulling aproximal end of the optical fiber, while maintaining the neuralstimulator in the vicinity of the SPG using a pusher.

For some applications, the optical fiber shape-sensing system includesoptical fiber shape-sensing circuitry and assessing includes assessing ashape of the palatine canal using the optical fiber shape-sensingcircuitry.

For some applications, assessing further includes assessing anorientation of the neural stimulator within the greater palatine canalusing the optical fiber shape-sensing system, based on a shape of theoptical fiber during advancement.

For some applications, assessing further includes assessing a locationof the neural stimulator within the greater palatine canal using theoptical fiber shape-sensing system, based on a shape of the opticalfiber during advancement.

For some applications, the method further includes navigating the neuralstimulator in the palatine canal based on the assessing of the shape ofthe palatine canal.

There is additionally provided in accordance with an application of thepresent invention apparatus for use with an optical fiber shape-sensingsystem, the apparatus including:

an implant including (a) a neural stimulator configured to applyelectrical stimulation to a sphenopalatine ganglion (SPG) of a subject,and (b) an optical fiber in contact with the neural stimulator, andoptically couplable to the optical fiber shape-sensing system, andconfigured to change shape during delivery of the implant to the SPGthrough a greater palatine canal of the subject; and

a delivery tool configured (a) to be removably coupled to the implant,(b) to deliver the implant to the SPG through the greater palatinecanal, and (c) to detach from the implant once the implant is deliveredto the SPG.

For some applications, a portion of the optical fiber is wrapped arounda portion of the neural stimulator.

For some applications, the optical fiber is configured to be decoupledfrom the neural stimulator by pulling a proximal end of the opticalfiber.

For some applications, the neural stimulator has a proximal portion, adistal portion and a middle portion between the proximal and distalportions, and the proximal portion is more rigid than the middleportion.

For some applications, the distal portion is more rigid than the middleportion.

For some applications, a portion of the optical fiber (a) is disposed inthe delivery tool, and (b) is shaped within the delivery tool such thatrelative motion between the implant and the delivery tool causes achange in the shape of the portion of the optical fiber.

For some applications, the portion of the optical fiber in the deliverytool is shaped to define a loop, such that distancing of the deliverytool from the implant causes a reduction in a diameter of the loop.

For some applications, the portion of the optical fiber in the deliverytool is shaped to define a curve, such that distancing of the deliverytool from the implant causes a straightening of the curve.

For some applications the apparatus further includes a proximity sensorconfigured to indicate that the delivery tool is detached from theimplant by generating a signal that varies in response to relativemotion between the delivery tool and the implant.

For some applications the proximity sensor includes at least oneradiofrequency (RF) coil coupled to the implant and at least one RF coilcoupled to the delivery tool.

For some applications the proximity sensor includes at least onemagnetic element coupled to the implant and at least one magneticelement coupled to the delivery tool.

There is further provided in accordance with an application of thepresent invention, a method including:

using an optical fiber shape-sensing system, assessing a travel path ofa neural stimulator advanced in a greater palatine canal toward asphenopalatine ganglion (SPG) of a subject, based on shape changes of anoptical fiber advanced toward the SPG along with the neural stimulator;

using a navigation system, assessing a travel path of the neuralstimulator in the canal based on movement of an optical marker attachedto a delivery tool used for advancing the neural stimulator;

generating an indication that there is an error in the travel pathassessed using the navigation system if (a) the travel path detectedusing the optical fiber shape-sensing system matches a pre-operativelydetermined shape of the canal and (b) the travel path assessed using thenavigation system indicates that the neural stimulator has passed out ofthe canal.

For some applications, the method further includes the step ofrecalibrating the navigation system by performing registration of theoptical marker, following generating the indication that there is anerror in the travel path.

There is further provided in accordance with an application of thepresent invention, a method including:

using an optical fiber shape-sensing system, assessing a travel path ofa neural stimulator in a greater palatine canal advanced toward asphenopalatine ganglion (SPG) of a subject, based on shape changes of anoptical fiber advanced toward the SPG along with the neural stimulator;

using a navigation system, assessing a travel path of the neuralstimulator in the canal based on movement of an optical marker attachedto a delivery tool used for advancing the neural stimulator;

generating an indication that there is an error in the travel pathassessed using at least one of the systems if (a) the travel pathassessed using the navigation system matches pre-operative registrationdata of the optical marker, and (b) the travel path detected using theoptical fiber shape-sensing system indicates that the neural stimulatorhas passed out of the canal; and

recalibrating the navigation system by performing registration of theoptical marker.

There is further provided in accordance with an application of thepresent invention, a method including:

advancing an optical fiber through a bony canal of a subject, theoptical fiber (a) being configured to change shape during advancementthrough the bony canal and (b) being optically coupled to optical fibershape-sensing system;

using the optical fiber shape-sensing system, assessing a shape of theoptical fiber during advancement through the bony canal; and assessing ashape of the bony canal based on the assessing of the shape of theoptical fiber.

There is further provided in accordance with an application of thepresent invention, apparatus including:

an implant including a neural stimulator configured to apply electricalstimulation to a sphenopalatine ganglion (SPG) of a subject, the implanthaving a maximum length of 4 cm and a maximum diameter of 3 mm;

a delivery tool configured (a) to be removably coupled to the implant,(b) to deliver the implant to the SPG through a greater palatine canal,and (c) to detach from the implant once the implant is delivered to theSPG; and

a proximity sensor configured to indicate that the delivery tool isdetached from the implant by generating a signal in response to relativemotion between the delivery tool and the implant.

There is further provided in accordance with an application of thepresent invention, apparatus including:

an oral surgical guide having a non-patient-customized portion and apatient-customized portion, the oral surgical guide including:

-   -   an arch portion configured to be placed on a dental arch of a        subject; and    -   an extension portion extending from the arch portion, and shaped        to define a guide hole.

There is further provided in accordance with an application of thepresent invention, a method including:

using an oral surgical guide generated using CT data to determine alocation of a greater palatine foramen of a palate of an oral cavity ofa subject;

inserting a steerable implantable neural stimulator mounted on adelivery guide into the greater palatine foramen of the subject, througha hole in the surgical guide;

advancing the stimulator through a greater palatine canal of the subjectto a sphenopalatine ganglion (SPG) of the subject; and

terminating the advancing of the stimulator based on contact of aportion of the delivery guide with a portion of the surgical guide thathas a length corresponding to a location of the SPG.

There is further provided in accordance with an application of thepresent invention, apparatus for use with an optical fiber shape-sensingsystem, the apparatus including:

an optical fiber, optically couplable to the optical fiber shape-sensingsystem, and configured to change shape during advancement through agreater palatine canal of a subject;

a delivery tool configured to be removably coupled to the optical fiberand to distally advance the optical fiber through the greater palatinecanal; and a neural stimulator implant, configured to apply electricalstimulation to a sphenopalatine ganglion (SPG) of the subject, and (i)not in contact with the optical fiber, and (ii) shaped and sized to bedelivered to the sphenopalatine ganglion (SPG) by the delivery tool.

For some applications, the neural stimulator implant is not disposedwithin the delivery tool.

For some applications, the optical fiber has a sensing length of 4-6 cm.

For some applications, the optical fiber has fiber Bragg gratings thatare positioned 2-5 mm apart from each other.

For some applications, the optical fiber shape-sensing system includesoptical fiber shape-sensing circuitry and the optical fiber is opticallycouplable to the optical fiber shape-sensing circuitry.

For some applications, the apparatus further includes a proximity sensorconfigured to indicate that the delivery tool is detached from theimplant by generating a signal that varies in response to relativemotion between the delivery tool and the implant.

For some applications, the neural stimulator has a proximal portion, adistal portion and a middle portion between the proximal and distalportions, and the proximal portion is more rigid than the middleportion.

For some applications, the distal portion is more rigid than the middleportion.

There is further provided in accordance with an application of thepresent invention, a method including:

using a delivery tool, distally advancing, through a greater palatinecanal of a subject, an optical fiber being configured to change shapeduring advancement through the greater palatine canal;

assessing a shape of the palatine canal using an optical fibershape-sensing system, based on a shape of the optical fiber duringadvancement;

removing the optical fiber from the greater palatine canal; andsubsequently to removing the optical fiber, distally advancing throughthe greater palatine canal a neural stimulator that is configured toapply electrical stimulation to a sphenopalatine ganglion (SPG) of thesubject.

For some applications, distally advancing the neural stimulator includesnavigating the neural stimulator in the palatine canal based on theassessing of the shape of the palatine canal.

For some applications, using the delivery tool includes navigating thedelivery tool in the palatine canal based on the assessing of the shapeof the palatine canal.

For some applications, assessing the shape of the palatine canal usingthe optical fiber shape-sensing system, includes mapping the palatinecanal based on a shape of the optical fiber during advancement.

For some applications, the method further includes implanting the neuralstimulator in a vicinity of the SPG.

For some applications, the optical fiber shape-sensing system includesoptical fiber shape-sensing circuitry and wherein assessing includesassessing a shape of the palatine canal using the optical fibershape-sensing circuitry.

For some applications the method further includes, using the deliverytool during the distal advancing thereof, widening the palatine canal inpreparation for advancing of the neural stimulator.

There is further provided in accordance with an application of thepresent invention, a method including:

using a delivery tool, advancing an optical fiber through a bony canalof a subject, the optical fiber (i) being configured to change shapeduring advancement through the bony canal and (ii) being opticallycoupled to optical fiber shape-sensing system;

using the optical fiber shape-sensing system, assessing a shape of theoptical fiber during advancement through the bony canal;

assessing a shape of the bony canal based on the assessing of the shapeof the optical fiber;

removing the optical fiber from the bony canal; and

subsequently to the removing, navigating an implant through the bonycanal.

For some applications, navigating the implant includes navigating theimplant in the bony canal based on the assessing of the shape of thebony canal.

There is further provided in accordance with an application of thepresent invention apparatus for use with an optical fiber shape-sensingsystem, the apparatus including:

an optical fiber, (i) optically couplable to the optical fibershape-sensing system, (ii) configured to change shape during advancementthrough a greater palatine canal of the subject, and (iii) shaped todefine a predetermined breaking point of the optical fiber between adistal portion of the optical fiber and a proximal portion of theoptical fiber, such that application of force to the predeterminedbreaking point causes breaking of the optical fiber at the predeterminedbreaking point;

a delivery tool configured (a) to be removably coupled to the opticalfiber, and (b) to distally advance the optical fiber through the greaterpalatine canal of the subject.

For some applications, the optical fiber is shaped to define a narrowportion which defines the predetermined breaking point.

For some applications, the apparatus further includes a sheath, and thepredetermined breaking point is disposed in the sheath.

For some applications, a length of the sheath is 2 mm-15 mm.

For some applications, the apparatus further includes a neuralstimulator fixed to the optical fiber and configured to apply electricalstimulation to a sphenopalatine ganglion (SPG) of a subject.

There is further provided in accordance with an application of thepresent invention, a method including:

using a delivery tool, distally advancing, through a greater palatinecanal of a subject, an optical fiber, the optical fiber being configuredto change shape during advancement of the neural stimulator through thegreater palatine canal;

assessing a shape of the palatine canal using an optical fibershape-sensing system, based on a shape of the optical fiber duringadvancement;

separating a distal portion of the optical fiber from a proximal portionof the optical fiber by applying force to a predetermined breaking pointin the optical fiber; and

removing the proximal portion of the optical fiber from the palatinecanal.

For some applications, a portion of the optical fiber including thepredetermined breaking point is disposed within a sheath during theapplying of the force to the predetermined breaking point.

There is further provided in accordance with an application of thepresent invention apparatus, including:

an oral surgical guide including:

-   -   an arch portion configured to be placed on a dental arch of a        subject;    -   an extension portion extending from the arch portion in a        superior and lingual direction with respect to the arch, and        shaped to define a guide hole; and    -   a support element extending from a left side of the arch portion        to a right side of the arch portion, posterior to a canine        region of the oral surgical guide.

The present invention will be more fully understood from the followingdetailed description of embodiments thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a system for delivery of a neural stimulator implant forelectrical stimulation of a sphenopalatine ganglion (SPG) of a subject,in accordance with some applications of the present invention;

FIG. 2 is a schematic illustration of a delivery guide being advancedthrough a guide hole of an oral surgical guide, in accordance with someapplications of the present invention;

FIGS. 3A, 3B, 3C, 3D, 3E, 3F, 3G and 3H are schematic illustrations ofvarious configurations of the surgical guide shaped to define a guidehole for locating the entrance to the greater palatine canal, inaccordance with some applications of the present invention;

FIGS. 4A, 4B, 4C, and 4D are schematic illustrations of the system fordelivery of a neural stimulator implant for electrical stimulation of asphenopalatine ganglion (SPG) of a subject, in accordance with someapplications of the present invention;

FIG. 5 is a schematic illustration of the neural stimulator implant forelectrical stimulation of a sphenopalatine ganglion (SPG) of a subject,in accordance with some applications of the present invention;

FIG. 6 is a schematic illustration of a tool for facilitating deliveryof a neural stimulator implant for electrical stimulation of asphenopalatine ganglion (SPG) of a subject, in accordance with someapplications of the present invention;

FIG. 7 is a schematic illustration of a tool for facilitating deliveryof a neural stimulator implant for electrical stimulation of asphenopalatine ganglion (SPG) of a subject, in accordance with someapplications of the present invention;

FIG. 8 is a schematic illustration of a neural stimulator implantmounted onto a tool for facilitating delivery thereof for electricalstimulation of a sphenopalatine ganglion (SPG) of a subject, inaccordance with some applications of the present invention;

FIGS. 9A and 9B are schematic illustrations of the neural stimulatorimplant, in accordance with some applications of the present invention;

FIG. 10 is a schematic illustration of the neural stimulator implant, inaccordance with some applications of the present invention;

FIG. 11 is a schematic illustration of the neural stimulator implanthaving a bent distal end, in accordance with some applications of thepresent invention;

FIGS. 12A, 12B and 12C are schematic illustrations of a tool comprisinga guiding groove for facilitating delivery of a neural stimulatorimplant for electrical stimulation of a sphenopalatine ganglion (SPG) ofa subject, in accordance with some applications of the presentinvention;

FIG. 13 is a block diagram showing steps for preparation of a surgicalguide, in accordance with some applications of the present invention;

FIGS. 14A and 14B are schematic illustrations of a neural stimulatorimplant and an optical fiber, mounted onto a delivery tool forfacilitating delivery of the implant, for electrical stimulation of asphenopalatine ganglion (SPG) of a subject, in accordance with someapplications of the present invention;

FIGS. 15A, 15B, 16 and 17 are schematic illustrations of a neuralstimulator implant and an optical fiber, in accordance with someapplications of the present invention;

FIGS. 18A, 18B and 18C are schematic illustrations of apparatuscomprising neural simulator, optical fiber and tool in accordance withsome applications of the present invention;

FIG. 19 is a flow chart showing a method for use in accordance with someapplications of the present invention;

FIG. 20 is a flow chart showing a method for use in accordance with someapplications of the present invention; and

FIG. 21 is a schematic illustration of apparatus comprising an opticalfiber and a delivery tool in accordance with some applications of thepresent invention.

DETAILED DESCRIPTION OF APPLICATIONS

Reference is made to FIG. 1, which is a schematic illustration of asystem 20 for delivery of a neural stimulator implant 32 for electricalstimulation of a sphenopalatine ganglion (SPG) of a subject, inaccordance with some applications of the present invention. Typically,system 20 includes neural stimulator implant 32, steerable deliveryguide 34, and an oral surgical guide 40.

Typically, neural stimulator implant 32 is configured to be passedthrough a greater palatine foramen of the hard palate of the oral cavityof the subject, into a greater palatine canal, such that the neuralstimulator implant is brought into a vicinity of a sphenopalatineganglion (SPG). For some applications, the implant is an elongated,flexible implant having an unconstrained shape and configured to conformto the anatomical structure of the greater palatine canal, foradvancement therethrough. For some applications, the implant comprisesat least one electrode, e.g., a wire electrode, for stimulation of theSPG. Typically, implant 32 is shaped to define a curved or bent distalend, which facilitates steering of the implant during the advancing ofthe implant in the canal. (For the purposes of the specification andclaims of the present patent application, the terms “curved” or “bent”with respect to the distal end of the implant are to be understood asinterchangeable.) Typically, following the advancing of the implant anddeployment thereof in the vicinity of the SPG, for some subjects, thedistal end of the implant is constrained and substantially not curveddue to the anatomy of the canal, which is generally straight in thevicinity of the SPG in these subjects. For other subjects, the canal iscurved in the vicinity of the SPG, and thus the distal end of theimplant is curved at its implantation site in the vicinity of the SPG.

For some applications, neural stimulator implant 32 is coupled tosteerable delivery guide 34. Implant 32 is configured to be passedthrough guide 34, such that both implant 32 and guide 34 are advancedthrough the greater palatine foramen into the greater palatine canal,and implant 32 is brought into a vicinity of a sphenopalatine ganglion(SPG). Steerable delivery guide 34 is retracted after placement ofimplant 32.

FIG. 1 shows an exploded view of neural stimulator implant 32 passedthrough delivery guide 34. Delivery guide 34 is typically less flexiblethan neural stimulator implant 32, and thereby facilitates smoothpassage of the implant through the greater palatine canal and properdelivery of implant 32 to the SPG.

For some applications, a distal end 33 of steerable delivery guide 34 isconfigured to puncture oral mucosa of the subject, allowing neuralstimulator implant 32 to be passed through the palate in aminimally-invasive procedure, without requiring a prior surgicalincision in the mucosa. Typically, the distal end of the steerabledelivery guide is also configured to be passed through the greaterpalatine foramen into the greater palatine canal. The delivery guide issteered in the canal in order to deliver the neural stimulator implantto the SPG. For some applications, neural stimulator implant 32 isconfigured to puncture or otherwise create an opening in the oral mucosaof the subject. Following insertion of implant 32 into the mucosa, thesurgeon may optionally seal the puncture site by applying pressure tothe puncture site in order to facilitate self-healing of the hole, e.g.,by keeping a finger on the puncture site.

FIG. 1 additionally shows surgical guide 40 (represented by the dottedstructure) placed on teeth 2 of a dental arch 54 of the subject. (It isto be understood that for subjects without teeth, guide 40 is placed onthe gums.) Surgical guide 40 is generated based on CT data of thesubject and typically serves as a guide for locating the entrance to thegreater palatine canal through the greater palatine foramen of the hardpalate. Surgical guide 40 comprises an arch portion 59 configured forplacement on dental arch 54, and an extension portion 58 (shown in FIGS.2-3) that extends away from the arch portion. The extension portion isshaped to define a guide hole 6 (shown in FIGS. 2-3), which provides anoperating physician with the location and preferred entry angle to thegreater palatine foramen. Typically the location and angle of theentrance to the canal, as well as the length of the canal, varies amongthe population. Therefore, surgical guide 40 allows safe and accurateentry into the canal, and navigation therethrough, in accordance withthe subject's anatomy, based on the CT data. Surgical guide 40additionally inhibits excessive insertion of implant 32 into the canal.

For some applications, a distal end 38 of an angular guide 36 is placedon extension portion 58 of surgical guide 40 to facilitate advancementof delivery guide 34 through guide hole 6 in surgical guide 40.Typically, distal end 38 plugs into hole 6, such that angular guide 36facilitates advancement of delivery guide 34 into hole 6 at thepreferred angle, based on the CT data. When angular guide 36 is lockedproperly in place with respect to surgical guide 40, delivery guide 34is released by turning knob 63 in order to allow advancement of guide 34through guide hole 6. A tool 70 is configured to direct advancement ofguide 34 through guide hole 6 and subsequently through the greaterpalatine foramen into the greater palatine canal. Handle 60 of tool 70is steered and/or advanced, in order to direct motion of steerabledelivery guide 34.

Typically, the passage of implant 32 and delivery guide 34 into thegreater palatine canal is facilitated by image-guided surgicaltechniques, e.g., using optical fiducial markers 50, 51 and 52 on tool70 (and/or fiducial markers on guide 34). For some applications, animage-guided surgery processor utilizes location data derived frommarkers 50, 51 and 52, in combination with fiducial markers on thesubject (e.g., placed on the teeth, face or a head of the subject) inorder to register the pre-operative CT data with the current position ofthe tool and thereby facilitate steering and advancement of steerabledelivery guide 34 through the greater palatine canal. Alternatively oradditionally, the image-guided surgery processor utilizes location dataderived from markers 50, 51 and 52 in combination with registration dataobtained by (a) contacting a tool with a fiducial marker to multiplespots on the subject's head that can also be identified in thepre-operative CT image, and/or (b) visualizing markers 50, 51, and/or 52when angular guide 36 is locked in place, for example, by pluggingdistal end 38 into guide hole 6 or by a locking mechanism (as describedherein below with reference to FIGS. 4A-C). For some applications,handle 60 comprises a linear and/or an angular encoder configured tofacilitate recording of location data indicative of the current positionand orientation of neural stimulator implant 32. It is noted that thefiducial markers described herein can be used both in order to identifylocations in the subject's anatomy, and also as a reference marker, inorder to continually allow the image-guided surgery processor toidentify a current position of the subject's head, which can move.

Additionally, slide-bar 57 on tool 70 facilitates advancement ofdelivery guide 34 distally through guide hole 6. Typically, slide-bar 57provides steering functionality for facilitating advancement of guide 34into the greater palatine canal. Bar 57 is typically slidable withrespect to handle 60. Advancement of slide-bar 57 with respect to handle60 advances delivery guide 34 through the greater palatine canal.Additionally or alternatively, marker 50 comprises steeringfunctionality and is rotated around a center thereof in order to steerguide 34 and neural stimulator implant 32 within the canal in order todeliver the neural stimulator implant to the SPG. Further additionallyor alternatively, handle 60 is rotated as indicated by arrow 13, inorder to advance and orientate steerable delivery guide 34 within thegreater palatine canal.

For some applications, additional steering options are employed to allowcontrol of the advancement of implant 32 within the canal. For example,using a joystick allows steering the implant in a left/right and up/downdirection, as well as rotation around an axis.

Typically, the greater palatine canal is curved and multiple openingsare naturally formed along the greater palatine canal. Therefore, propersteering of guide 34 within the canal generally ensures delivery ofguide 34 and neural stimulator implant 32 to the SPG.

For some applications, surgical guide 40 is coupled to or used inassociation with a second arch portion (not shown). The second archportion is typically configured for placement on a lower dental arch ofthe subject. The second arch portion typically stabilizes upper archportion 59, by pressing portion 59 against the upper teeth and palate.Additionally or alternatively, a stabilizing element 90 is placedbetween the lower and upper dental arches of the subject, andfacilitates the squeezing of arch portion 59 against the upper teeth andpalate.

Reference is made to FIG. 2, which is a schematic illustration ofsteerable delivery guide 34 being steered and advanced through guidehole 6 of surgical guide 40, in accordance with some applications of thepresent invention. Surgical guide 40 comprises arch portion 59configured for placement on dental arch 54 and extension portion 58which is shaped to define guide hole 6. Extension portion 58 contactsthe roof of the oral cavity of the subject, and guide hole 6 is therebyautomatically placed over the entrance to the greater palatine foramenof the subject.

Thus, in accordance with some applications of the present invention,surgical guide 40 is configured to guide an operating physician to thelocation of the greater palatine foramen of the subject, to facilitateadvancement of guide 34 therethrough. Additionally, guide hole 6 in thesurgical guide facilitates penetration of the mucosa at an appropriateangle for entrance into the greater palatine foramen at an anglesuitable for advancement of guide 34 through the canal. Furtheradditionally, the CT data in combination with the surgical guide providethe operating physician with information regarding the anatomicalstructure of the greater palatine canal, thereby facilitating navigationand advancement of neural stimulator implant 32 coupled to steerabledelivery guide 34 through the canal.

For some applications, a length of a portion (e.g., a protrusion) ofsurgical guide 40 controls the degree to which neural stimulator implant32 may be inserted into the canal. In other words, the length of theportion (e.g., protrusion) inhibits excessive insertion of implant 32into the canal, and is designed such that the length of the portioncontrols the distance to which neural stimulator implant 32 is advancedin the canal. Thus, advancement of implant 32 is terminated based oncontact of a portion of the delivery guide with the portion of thesurgical guide that has a length corresponding to the location of theSPG. The location of the SPG and the shape of the canal are assessed bya pre-operative CT scan, and surgical guide 40 is typically configuredto facilitate insertion of neural stimulator implant 32 to the locationof the SPG based on the CT scan data. The shorter the length of theportion (e.g., the protrusion) of surgical guide 40, the farther neuralstimulator implant 32 is advanced in the canal.

FIGS. 3A-B are schematic illustrations of surgical guide 40 comprisingarch portion 59 configured for placement on teeth 2 of a subject, or ongums of the subject, in accordance with some applications of the presentinvention. Extension portion 58 extends, lingually and in a superiordirection, away from arch portion 59 and is placed in contact with theroof of the oral cavity of the subject. Extension portion 58 is shapedto define guide hole 6, which is automatically placed over the entranceto the greater palatine foramen when surgical guide 40 is placed onteeth 2, or gums, of the subject. For some applications, an adhesive,e.g., glue, is used to secure guide 40 to the teeth or gums of thesubject.

Typically the location of the greater palatine foramen varies among thepopulation. For example, in some subjects the greater palatine foramenis associated with the upper third molar tooth. In other subjects, thegreater palatine foramen is associated with the second molar or betweenthe second and third molar. It is noted that the location of guide hole6 is shown in the figures by way of illustration and not limitation. Itis understood that the location of guide hole 6 is set based on thelocation of the greater palatine foramen of each particular subject.Surgical guide 40 is typically custom-made based on a CT scan of thesubject, such that guide hole 6 is placed over the greater palatineforamen of each individual subject, in order to guide the physician tothe correct location.

Reference is now made to FIG. 3C. For some applications, surgical guide40 comprises a second extension portion 58 located contralateral toextension portion 58, for bilateral electrical stimulation of the rightand left SPG (e.g., for treatment of vascular dementia).

For some applications, surgical guide 40 is fabricated bythree-dimensional (3D) printing. For some applications, for example inorder to reduce fabrication time of guide 40, guide 40 comprises anon-patient-customized portion (e.g., made of metal, molded plastic, ageneric part made of a 3D-printed material, and/or a combination ofmaterials (e.g., a combination of plastic and metal), and apatient-customized portion (e.g., produced by 3D printing especially forthe patient).

Alternatively, surgical guide 40 is manufactured by molding a pliablematerial, such as a thermoplastic sheet, and drilling guide hole 6 witha drill. (After the molding, a suitable process is used to make thepliable material generally rigid, e.g., by heat treatment or ultravioletcuring.)

Typically, the drill has markers (e.g., RF coils, or optical markers) inorder to ensure drilling of guide hole 6 in a proper locationcorresponding to the greater palatine foramen. Typically, prior todrilling of the hole, the unfinished surgical guide is placed on teethor gums of the subject and CT data of the oral cavity is acquired.Subsequently, the surgical guide is removed from the subject's mouth.Using a processor, the CT data of the oral cavity with the surgicalguide is received and is used to determine a desired position of thedrill. Directional and orientational guidance for performing thedrilling is generated using the one or more markers on the drill.Subsequently, the processor guides drilling of the hole in the surgicalguide at a site on the surgical guide which corresponds to the greaterpalatine foramen of the subject.

Reference is now made to FIG. 3D. For some applications, surgical guide40 additionally comprises a support element 580. Support element 580typically extends from a first side of surgical guide 40 to a secondside of guide 40 (e.g., an opposite side, e.g., extending from the leftto the right side). Support element 580 typically extends from a leftside of arch portion 59 to a right side of arch portion 59, posterior toa canine region of oral surgical guide 40. Support element 580 typicallyenhances rigidity of guide 40 and inhibits movement of surgical guide 40when pressure is applied to guide 40 during insertion of angular guide36 through hole 6. Additionally or alternatively, surgical guide 40 isthickened in order to add to rigidity thereto, optionally in the absenceof support element 580.

Reference is now made to FIGS. 3E and 3F. For some applications,surgical guide 40 comprises a support element 582. Support element 582typically extends from extension portion 58 to a right side of archportion 59, posterior to a canine region of oral surgical guide 40.Support element 582 is generally the same as support element 580 andenhances rigidity of guide 40 and inhibits movement of surgical guide 40when pressure is applied to guide 40 during insertion of (for example)angular guide 36 through hole 6.

Reference is now made to FIGS. 3G and 3H. For some applications,surgical guide 40 comprises a support element 584. Support element 584typically extends from a left side of arch portion 59 to a right side ofarch portion 59, posterior to a canine region of oral surgical guide 40and inferior and in a lingual direction with respect to arch 59 (i.e.,more at the level of the teeth than at the level of the palate). Forsuch applications, support element 584 is shaped to define a guide hole6 a which is aligned with guide hole 6 in extension portion 58, allowingaccess to guide hole 6 through guide hole 6 a. Optionally but notnecessarily hole 6 a is shaped to define a funnel. Support element 584enhances rigidity of guide 40 and inhibits movement of surgical guide 40when pressure is applied to guide 40 during insertion of angular guide36 through hole 6.

Reference is made to FIGS. 4A-C, which are schematic illustrations ofdental arch portion 59, comprising a locking mechanism 94, in accordancewith some applications of the present invention. Locking mechanism 94 isconfigured to lock tool 70 and angular guide 36 in place with respect tosurgical guide 40, such that delivery guide 34 and implant 32 areadvanced accurately through guide hole 6. Generally, locking mechanism94 comprises (a) a projecting portion of surgical guide 40 which istypically shaped to provide a screw thread on an outer surface ofprojection 72, and (b) a screw thread on an inner surface of the lockingportion on tool 70. The screw threads on projection 72 and on tool 70engage each other, thereby locking the projection to the tool.

FIG. 4A shows surgical guide 40 comprising arch portion 59 and extensionportion 58. For some applications, extension portion 58 furthercomprises projection 72, which protrudes away from extension portion 58.Projection 72 is typically shaped to define the screw thread profiledescribed hereinabove, on an outer surface of the protrusion (as shown).(Alternatively, the screw-thread is on the inner surface of theprojection.)

Reference is made to FIG. 4B. For some applications, angular guide 36,which is mounted to tool 70, comprises locking portion 46 which isshaped to define a screw thread (described hereinabove), configured toengage projection 72 on surgical guide 40. Locking portion 46 istypically rotated in order to lock locking portion 46 to projection 72,thereby restricting motion of delivery guide 34.

FIG. 4C shows locking mechanism 94 in a locked state thereof. It is tobe noted that surgical guide 40 is shaped to define a screw-shapedprojection 72 by way of illustration and not limitation. In general,surgical guide 40 may comprise a first coupling, and guide 36 and/ortool 70 may comprise a second coupling. The first coupling may comprisea male coupling while the second coupling may comprise a femalecoupling, or vice versa.

It is noted that locking mechanism 94 is described by way ofillustration and not limitation. For some applications, tool 70 andangular guide 36 are locked in place with respect to surgical guide 40by plugging distal end 38 into guide hole 6. For example, locking oftool 70 with respect to surgical guide 40 is allowed when angular guide36 is plugged into guide hole 6 at an appropriate angle and/or aparticular orientation (e.g., via a fin extending at 12 o'clock thatfits into a corresponding slot on surgical guide 40).

Reference is made to FIG. 5, which is a schematic illustration of anexample of neural stimulator implant 32 for electrical stimulation of asphenopalatine ganglion (SPG) of the subject, in accordance with someapplications of the present invention.

Neural stimulator implant 32 is typically 0.5-1.5 mm in diameter, e.g.,1 mm. Thus, advancement of implant 32 typically does not requiredilation of the greater palatine canal. Alternatively, placement ofimplant 32 includes pre-dilation of the greater palatine canal.

For some applications, neural stimulator implant 32 is electricallycoupled to circuitry 56 which is adapted to be placed outside thegreater palatine canal, e.g., the circuitry may be positionedsubmucosally in the oral cavity. For other applications, circuitry 56 isadapted for insertion into the oral mucosa of the subject. Followinginsertion of electronic circuitry 56 into the mucosa, the surgeon mayseal the puncture site by applying pressure to the puncture site inorder to facilitate self-healing of the hole, e.g., by keeping a fingeron the puncture site. Typically, neural stimulator implant 32 itself isconfigured for puncturing the oral mucosa.

For some applications, electronic circuitry 56 is advanced along anexterior of delivery guide 34 (as shown), until circuitry 56 is insertedinto the mucosa.

As shown in FIG. 5, implant 32 typically comprises at least two steeringwires 101 configured to facilitate steering of implant 32 within thegreater palatine canal. Additionally, implant 32 comprises a stimulationwire 102 coupled to an electrode 106, for electrical stimulation of thesphenopalatine ganglion (SPG) of the subject, once implant 32 isdelivered to the vicinity of the SPG.

Typically, the delivery apparatus comprises a pusher 104 disposed withindelivery guide 34 (FIG. 1), which is configured to advance implant 32within the greater palatine canal, e.g., by pushing an inner surface ofelectrode 106.

Reference is made to FIG. 6, which is a schematic illustration of adelivery tool 700 for facilitating delivery of a neural stimulatorimplant 320 (described hereinbelow with reference to FIGS. 9A-B and 10)to a sphenopalatine ganglion (SPG) of a subject, for electricalstimulation of the SPG, in accordance with some applications of thepresent invention.

Tool 700 is typically used in combination with surgical guide 40(described herein with reference to FIGS. 3A-C) and directs advancementof the neural stimulator implant through guide hole 6 in surgical guide40 and subsequently through the greater palatine foramen into thegreater palatine canal.

Tool 700 typically comprises a handle 600 and a distal tip portion 720.In general, prior to use, the neural stimulator implant is mounted indistal tip portion 720. FIG. 6 shows the implant partially protrudingfrom tip portion 720, as it appears after it has been initially advancedinto the greater palatine canal. (For clarity of illustration, surgicalguide 40 and anatomy are not shown.) Overall, tool 700 facilitatesadvancement of the implant toward the sphenopalatine ganglion (SPG) of asubject.

Typically, distal tip portion 720 plugs into surgical guide 40 tofacilitate accurate advancement of neural stimulator implant 320 throughguide hole 6 in surgical guide 40. Handle 600 comprises a slide-bar 570,which is slidable with respect to handle 600. Slide-bar 570 is typicallylocked in place, until it is released by a release mechanism 730 (e.g.,by turning a knob on handle 600), in order to allow advancement of theneural stimulator implant through the guide hole and into the greaterpalatine canal.

An operating physician typically slides slide-bar 570 along handle 600in order to advance implant 320 out of tool 700 and distally throughguide hole 6. Additionally, slide-bar 570 provides steeringfunctionality for facilitating orientation of the implant in the greaterpalatine canal. Advancement of slide-bar 570 with respect to handle 600advances the implant through the canal.

For some applications, slide-bar 570 is rotated as indicated by arrow130, in order to orient implant 320 within the greater palatine canal.Typically, a distal-most portion of implant 320 is oriented at anon-zero angle with respect to a longitudinal axis of the implant, suchthat the implant may be steered in the palatine canal in an analogousfashion to that in which a steerable guidewire is steered in thevasculature of a subject.

For some applications, the passage of implant 320 into the greaterpalatine canal is facilitated by image-guided surgical techniques, e.g.,using optical fiducial markers 500, 510 and 520 on tool 700. Two or morecameras 16 are used to image markers 500, 510, and 520. An image-guidedsurgery processor 18 coupled to receive the image data from the camerasutilizes location data derived from markers 500, 510 and 520, incombination with fiducial markers on the subject (e.g., placed onsurgical guide 40, or the teeth, face or a head of the subject) toregister pre-operative CT data (showing bony structures in general andthe greater palatine canal in particular) with the current position ofthe tool and thereby facilitate steering and advancement of implant 320through the greater palatine canal.

Alternatively or additionally, the image-guided surgery processorutilizes location data derived from markers 500, 510 and 520 incombination with registration data obtained by (a) contacting a toolwith a fiducial marker to multiple spots on the subject's head that canalso be identified in the pre-operative CT image, and/or (b) visualizingmarkers 500, 510, and/or 520 when distal tip portion 720 is secured tosurgical guide 40.

For some applications (in addition to or instead of using markers 500,510, and 520), handle 600 comprises a linear and/or an angular encoderconfigured to facilitate recording of location data indicative of thecurrent position and orientation of neural stimulator implant 320.

It is noted that processor 18 is typically a programmed digitalcomputing device comprising a central processing unit (CPU), randomaccess memory (RAM), non-volatile secondary storage, such as a harddrive or CD ROM drive, network interfaces, and/or peripheral devices.Program code, including software programs, and/or data are loaded intothe RAM for execution and processing by the CPU and results aregenerated for display, output, transmittal, or storage, as is known inthe art. Such program code and/or data, when provided to the processor,produce a machine or special-purpose computer, configured to perform thetasks described herein.

Reference is made to FIG. 7, which is a schematic illustration ofdelivery tool 700, generally as described herein with reference to FIG.6. For some applications, slide-bar 570 of handle 600 comprises a distalportion 65 and a proximal portion 64, which are held connected to eachother by first and second magnetic elements 85 and 84 coupled to theproximal and distal portion of slide-bar 570 and magnetically coupled toeach other. Proximal portion 64 of slide-bar 570 is coupled to implant320 such that distal advancement of proximal portion 64 of the slide-barproduces distal advancement of the implant. Typically, the physicianadvances the slide-bar by gripping distal portion 65 and applying adistally-directed force thereto, such that the magnetic coupling causesproximal portion 64 to advance distally, and thereby cause distaladvancement of implant 320. If the force applied to distal portion 65 ofslide-bar 570 in a distal direction exceeds a threshold (e.g., due toadvancement of the implant being impeded), this typically breaks thecoupling between the first and second magnetic elements, therebydiscontinuing advancement of implant 320 and alerting the operatingphysician to an issue relating to the proper placement of implant 320.

Reference is made to FIG. 8, which is a schematic illustration of neuralstimulator implant 320 extending from distal tip portion 720 of tool700, in accordance with some applications of the present invention.(Other components of tool 700 are labeled 721 in FIG. 8). For someapplications, tool 700 comprises at a distal portion thereof, astainless steel tube 780 configured to engage a locking element 350 ofimplant 320. An engaging element 781 is configured to engage lockingelement 350 of implant 320 (shown in FIG. 8 as a ball by way ofillustration and not limitation). Typically, activation of animplant-release mechanism 630 (e.g., by turning a knob as shown in FIG.6) causes engaging element 781 to disengage from locking element 350,allowing all implantation apparatus in the greater palatine canal to bewithdrawn, generally without dislodging implant 320 from itsimplantation location near the SPG.

Typically, tube 780 is shaped to define a series of slits 324longitudinally aligned along tool 700, each slit disposed at an angularoffset (e.g., a 180 degree offset as shown in FIG. 8, or alternativelyat a 90 degree offset, not shown) from an adjacent one of the slits. Theslits permit tube 780 to bend in a range of directions, e.g., in anydirection, to facilitate advancement of the implant through the greaterpalatine canal.

Implant 320 is generally flexible but typically also comprises a rigidportion 321 which houses a receiving coil 322 configured to receivepower from a remote power source to power implant 320.

Reference is now made to FIGS. 9A-11, which are different views ofimplant 320, in accordance with some applications of the presentinvention. As shown, implant 320 comprises proximal 352 and distal 354portions. Implant 320 is a generally flexible, elongate implant havingelectrodes (e.g. a dome electrode 12 and a second electrode 14) at thedistal portion thereof and an unconstrained shape that is curved, i.e.,bent, in a vicinity of the distal portion (e.g., proximal to electrode14, or between electrodes 12 and 14). FIGS. 9A-B and 10 show implant 320in a straight configuration. Typically, following the advancing of theimplant and deployment thereof in the vicinity of the SPG, distalportion 354 of the implant is constrained and shaped differently due tothe anatomy of the canal compared to its unconstrained shape. Forexample, distal portion 354 may be generally straight in the vicinity ofthe SPG, based on the anatomy of some subjects, or distal portion 354may be curved at its implantation site in the vicinity of the SPG.

Implant 320, in particular distal portion 354, is typically configuredto puncture oral mucosa of the subject in order to allow advancement ofimplant 320 into the greater palatine canal. For some applications,implant 320 is not configured to puncture the oral mucosa, but instead adistal portion of tool 700 is configured to puncture oral mucosa.

It is noted that for some applications, implant 320 comprises two ormore portions of electronic circuitry comprising multiple circuitryunits 326, at discrete longitudinal sites along implant 320 (shown inFIG. 10). Typically, the electronic circuitry is divided into first andsecond portions 17 and 19, which are coupled respectively to proximaland distal sites of neural stimulator implant 320 that are flexiblycoupled to each other. Division of the electronic circuitry into two ormore portions typically facilitates smooth advancement of the implant inthe canal.

For some applications, a flexible, connecting element 328 (e.g., aflexible printed circuit board) extends along implant 320 and connectsfirst and second portions 17 and 19 of the electronic circuitry.Alternatively or additionally, a structural element 325 able towithstand compressive forces associated with the implantation is used toconvey distally-directed forces toward the distal end of implant 320.For example, this structural element may comprise nitinol (and for someapplications is not used to convey electrical signals between the firstand second portions of the electronic circuitry). Structural element 325comprising nitinol typically has a trained natural curve, which enablessteering of implant 320 by rotating the handle 600 of tool 700 (FIG. 6).The curve in element 325 could be as shown in FIG. 11, or between thetwo electrodes on distal portion 354, or within 15 mm of the very distaltip.

FIG. 11 shows neural stimulator implant 320 having a curved or bentdistal end, as described hereinabove, in accordance with someapplications of the present invention.

Reference is made to FIGS. 1-12C and FIGS. 14A-18C. For someapplications, a surface shaped to define a guiding groove is generated(typically by a 3D printing process) based on CT data obtained byimaging the subject. Based on the CT data, the guiding groove is shapedin accordance with the subject's anatomy in order to guide the implantto the desired anatomical site, e.g., to guide steering of neuralstimulator implants 32 and/or 320 through the greater palatine canal tothe vicinity of the sphenopalatine ganglion (SPG).

As shown in FIG. 12, a delivery tool, e.g., implantation tool 700,comprises a surface shaped to define a curved guide groove 920 at aproximal portion 710 of the delivery tool. Curved guide groove 920 isgenerated based on data obtained by imaging the anatomy of the subject,e.g., the greater palatine canal. A guiding pin 940 is typicallydisposed within curved guide groove 920, and is configured such thatadvancement of slide-bar 570 with respect to proximal portion 710produces (1) relative motion of guiding pin 940 with respect to curvedguide groove 920, and (2) rotation of slide-bar 570 with respect to alongitudinal axis of tool 700.

Typically, as the operating physician slides slide-bar 570 along handle600, guide groove 920 correctly guides the pin, thereby steering theimplant in the canal (i.e., by causing rotation of slide-bar 570 asindicated by arrow 130 in FIG. 6, at the correct point in thelongitudinal advancement of slide-bar 570 to cause a correspondingsteering of implants 32 and/or 320).

For some applications, guiding pin 940 is attached to delivery tool 700,e.g., guiding pin 940 is fixedly coupled to slide-bar 570 of tool 700.For such applications, the surface shaped to define curved guide groove920 is a surface of tool 700. For other applications, guiding pin 940 isattached to tool 700 (e.g., to handle 600 and not to the slide-bar) andslide-bar 570 is shaped to define the surface with curved guide groove920.

It is noted that these applications using the guiding groove may, buttypically do not, utilize optical markers 500, 510, or 520, or manyother electronic surgical guidance techniques known in the art. For someapplications, the techniques described in this paragraph may be used foradvancement of other tools, in sites other than the greater palatinecanal (e.g., to facilitate endoscopic sinus surgery, or vascularcatheterizations).

Reference is made to FIGS. 3A-B and FIG. 13. For some applications,surgical guide 40 is generated based on data from both a CT scan and anintra-oral scan. For such applications, an intra-oral scan of the upperpalate of the subject is performed in addition to the CT scan, and thedata from both scans are registered for preparation of surgical guide40.

An intra-oral scan typically contributes to fabrication of abetter-fitting surgical guide 40 by providing high-resolution data ofthe upper palate including mapping of soft-tissue anatomy such as oralmucosa. For example, a portion of surgical guide 40 that corresponds toa surface of gum tissue of the subject is typically shaped in a curvedmanner that matches curvature of the gum tissue.

Thus, hole 6 is properly placed over the soft tissue that covers thegreater palatine foramen. Having the surgical guide fit better over theoral mucosa typically facilitates optimal puncturing and penetration ofthe greater palatine foramen.

As described hereinabove, data obtained from the CT scan regarding boneand hard tissue of the subject, are typically used to determine thelocation and angle of implant insertion as well as guiding advancementof the implant to the SPG. Combining the data from both the CT scan andthe intra-oral scan typically results in an enhanced surgical guide 40in which both bone structure and the shape of soft tissue of the oralcavity are both reflected in surgical guide 40.

FIG. 13 is a block diagram showing steps of obtaining both CT scan dataand intra-oral scan data for preparation of a surgical guide, inaccordance with some applications of the present invention. Typically,in step 80, a subject in need of electrical stimulation of the SPG isidentified. A CT scan and an intra-oral scan are then performed, asshown in steps 81 and 82. In step 83 the data from the CT and intra-oralscans are registered, and subsequently the surgical guide is planned andfabricated using the data from both the CT and intra-oral scanning(steps 86 and 87). As described hereinabove, surgical guide 40 istypically fabricated by three-dimensional printing techniques.

It is however noted that for some applications, surgical guide 40 isgenerated based on CT data only. Alternatively, for some applications,surgical guide 40 is generated based on intra-oral scan data only.

For some applications in which surgical guide 40 is generated based onintra-oral scan data only, a CT scan is performed after surgical guide40 is generated. For example, CT data of the subject may be acquiredwhile surgical guide 40 is disposed within the oral cavity, andregistration of surgical guide 40 with respect to hard tissue of theanatomy may be performed using one or more markers affixed to surgicalguide 40, and/or using features of the anatomy (e.g., teeth) that areimaged in the CT scan and in the intra-oral scan. The CT data typicallyguide the surgeon to drill a hole in surgical guide 40 at a site on thesurgical guide that corresponds to the greater palatine foramen of thesubject. For example, this drilling may be facilitated by markers on thedrill, as described hereinabove. Subsequently, to drilling the hole,surgical guide 40 may be placed in the mouth and used to facilitate aprocedure, as described hereinabove.

Reference is now made to FIGS. 14A-B, which are schematic illustrationsof apparatus 200 comprising neural stimulator implant 320 mounted ontodelivery tool 700, in accordance with some applications of the presentinvention.

For applications shown in FIGS. 14A-17, neural stimulator implant 320additionally comprises a shape-sensing optical fiber 420. Optical fiber420 is optically couplable to an optical fiber shape-sensing system 426(FIG. 16, not to scale), and is configured to change shape duringdelivery of implant 320 to the SPG through the greater palatine canal ofthe subject.

In accordance with shape-sensing optical fiber technology, optical fiber420 is typically used to monitor a dynamic three-dimensional shape of astructure to which it conforms. In the context of the presentapplication, optical fiber 420 is typically used to assess athree-dimensional shape of the greater palatine canal and monitoradvancement and navigation of implant 320 distally in the canal bymonitoring changes in the shape of optical fiber 420 during advancement.

Additionally or alternatively, optical fiber 420 is used to assess aposition of neural stimulator implant 320 within the greater palatinecanal based on a shape of the optical fiber during advancement.Typically, use of optical fiber 420 facilitates verifying orientationand location of implant 320 during and following deployment of theimplant in the vicinity of the SPG, such that a post-operative CT scanis in many cases not necessary.

As noted hereinabove, optical fiber 420 is optically couplable tooptical fiber shape-sensing system 426. The optical fiber shape-sensingsystem typically comprises fiber shape-sensing circuitry configured toprocess the optical signal from the optical fiber and generate an outputindicative of the dynamic shape of optical fiber 420. (Typically theoptical fiber shape-sensing circuitry 428 comprises a circuitry unitintended for multiple uses.) It will be appreciated that circuitry 428may be standard circuitry of a multi-purpose computer, which performsthe desired shape sensing operations due to software running on thecomputer.

FIG. 15A is a schematic illustration of implant 320 and optical fiber420. Typically optical fiber 420 contacts implant 320. For example,optical fiber 420 may be wrapped around a portion of neural stimulatorimplant 320, e.g., wrapped around distal portion 354 of the implant.

For some applications, optical fiber 420 is fixed to neural stimulatorimplant 320, and can only be separated from the implant by permanentlychanging a component (e.g., by cutting the fiber). In theseapplications, at least a portion of optical fiber 420 remains implantedat the SPG. For some applications, optical fiber 420 is shaped to definea predetermined breaking point 490 of optical fiber 420 between a distalportion 494 of optical fiber 420 and a proximal portion 492 of opticalfiber 420, such that application of force to predetermined breakingpoint 490 causes breaking of optical fiber 420 at predetermined breakingpoint 490. For some applications, predetermined breaking point 490 isshaped to define a narrow portion of optical fiber 420. Breaking ofoptical fiber 420 at predetermined breaking point 490 typicallyfacilitates separating of proximal portion 492 from distal portion 494(e.g., by pulling), and subsequent removal of proximal portion 492 fromthe palatine canal. Distal portion 494 typically remains implanted atthe SPG (typically along with neural stimulator implant 320).

For some applications, optical fiber 420 is shaped to define more thanone predetermined breaking point 490. For example, when optical fiber420 is wrapped around a portion of neural stimulator implant 320, asshown in FIGS. 15A and 15B, optical fiber 420 may have a secondpredetermined breaking point 490 allowing removal of both proximal endsof optical fiber 420.

For some applications, optical fiber 420 is partly disposed within asheath 450 such that predetermined breaking point 490 is disposed withinsheath 450. Typically, some or all residue that may occur as a result ofbreaking of fiber 420 at predetermined breaking point 490 is containedin sheath 450.

Typically sheath 450 has a length of at least 2 mm and/or less than 15mm, e.g., at least 5 mm and/or less than 10 mm. For some applications,as shown in FIG. 15B, only a small portion of proximal portion 492 isdisposed in sheath 450, facilitating ease of removal of proximal portion492 from the palatine canal.

Typically, sheath 450 stays in place after breaking of fiber 420 andremoval of proximal portion 492 from the palatine canal. For someapplications, sheath 450 is mechanically coupled to distal portion 494,e.g., glued to distal portion 494 or held by friction to distal portion494, thus keeping sheath 450 in place after breaking of fiber 420.

Alternatively, sheath 450 may be pulled out of the palatine canal alongwith proximal portion 492. For example, the position of predeterminedbreaking point 490 within sheath 450 may define whether sheath 450slides out of the palatine canal along with proximal portion 492 whenproximal portion 492 is pulled proximally. For example, if most of theportion of fiber 420 that is disposed in sheath 450 is part of proximalportion 492, sheath 450 is likely to be pulled out of the palatine canalalong with proximal portion 492.

Alternatively or additionally, for some applications, optical fiber 420is coupled to tool 700 and is not in contact with implant 320, and isadvanced distally in the greater palatine canal while coupled to tool700. Applications in which optical fiber 420 is coupled to tool 700 andis advanced distally in the greater palatine canal in the absence ofimplant 320 are described hereinbelow with reference to FIG. 21.

FIGS. 15A and 15B show proximal, distal and middle portions of implant320, in accordance with some applications of the present invention.Typically proximal portion 352 is more rigid than middle portion 351.Additionally, distal portion 354 is more rigid than middle portion 351(middle portion 351 typically includes connecting element 328 describedhereinabove with reference to FIG. 10).

Reference is again made to FIGS. 14A-B. Tool 700 is typically removablycoupled to implant 320 and is configured to deliver the implant to theSPG through the greater palatine canal. Following deployment of implant320 in the vicinity of the SPG, tool 700 detaches from implant 320. Forsome applications, tool 700 comprises a detachment mechanism configuredto detach the delivery tool from implant 320 (e.g., a spring-basedrelease mechanism, as is generally known in the art). For someapplications, the cutting tool cuts fiber 420 without detaching implant320 from tool 700, and typically after implant 320 has been detachedfrom tool 700. For some applications, the detachment mechanism comprisesa cutting tool, configured to detach tool 700 from the implant bycutting optical fiber 420.

For some applications, in which optical fiber 420 is not fixed toimplant 320, optical fiber 420 is decoupled from the neural stimulatorimplant by pulling a proximal end of the optical fiber. Typically, whilepulling optical fiber 420, implant 320 is maintained in place by tool700 (or by additional mechanical elements). For example, a pusher may beused to maintain implant 320 in the vicinity of the SPG, while opticalfiber 420 is being pulled and decoupled from implant 320. As shown forexample in FIG. 15, optical fiber 420 wraps around the distal end ofimplant 320, such that by pulling optical fiber 420 while holdingimplant 320 in place, optical fiber 420 is entirely removed from contactwith the implant.

It is noted that the scope of the present invention includes usingoptical fiber 420, even without an implant, to assess a shape of a bonycanal (not necessarily the greater palatine canal), by assessing a shapeof the optical fiber during advancement through the bony canal.

Reference is now made to FIGS. 18A-C, which are schematic illustrationsof apparatus 200 comprising neural simulator implant 320, optical fiber420 (removably coupled or fixed to implant 320) and tool 700 inaccordance with some applications of the present invention. As shown inFIGS. 18A-C, optical fiber 420 is used to assess proper detachment ofimplant 320 from tool 700. Typically, once delivery tool 700 reaches theimplantation site (i.e., the vicinity of the SPG), implant 320 isdeployed at the implantation site by detaching from tool 700. Tool 700is subsequently pulled back through the greater palatine canal andremoved from the body of the subject. In cases in which detachment ofimplant 320 from tool 700 is not complete, implant 320 may be(undesirably) pulled back proximally in the canal together with tool700, instead of properly remaining at the implantation site. Thus, forsome applications, optical fiber 420 is used to assess proper detachmentof implant 320 from tool 700 by monitoring a change in a shape of fiber420. For such applications, a portion of optical fiber 420 is disposedin tool 700 and is shaped within tool 700 such that relative motionbetween implant 320 and delivery tool 700 (e.g., distancing of tool 700from implant 320) causes a change in the shape of the portion of theoptical fiber in tool 700.

As shown in FIGS. 18A-C, for some applications, the portion of opticalfiber 420 in tool 700 is shaped to define a loop 424, such thatdistancing of the delivery tool from the implant causes a reduction in adiameter of the loop. FIG. 18A shows implant 320 coupled to opticalfiber 420 and mounted onto tool 700 while being distally advanced incanal 900. A portion of fiber 420 is additionally disposed in tool 700and is shaped to define a loop 424 during distal advancement of tool700. When proper detachment of implant 320 from tool 700 is achieved atimplantation site 910, tool 700 is distanced from implant 320 byslightly pulling tool 700 back in the canal. Distancing of the tool fromthe implant naturally causes a reduction in a diameter of loop 424,e.g., from D1 to D2 (FIG. 18B), since fiber 420 is held on either end bytool 700 and implant 320 while they are separating. The reduction in thediameter of loop 424 typically indicates proper decoupling of tool 700from implant 320. Once proper decoupling is indicated, fiber 420 is cutat the distal portion of tool 700, and tool 700 is removed from the bodyof the subject. When proper decoupling of tool 700 and implant 320 isnot achieved (FIG. 18C), this is indicated by tool 700 being pulledproximally in the canal together with implant 320, and a diameter ofloop 424 remaining generally unchanged, indicating insufficientdetachment of implant 320 from tool 700.

It is noted that loop 424 is shown by way of illustration and notlimitation. The scope of the present invention includes additional oralternative non-straight shapes of the portion of fiber 420 that isdisposed in tool 700. For example, the portion of optical fiber 420 indelivery tool 700 may be shaped to define a curve, such that distancingof delivery tool 700 from implant 320 causes a straightening of thecurve.

Additionally or alternatively, apparatus 200 further comprises aproximity sensor configured to indicate that tool 700 is detached fromimplant 320 by generating a signal that varies in response to relativemotion (e.g., distancing) between delivery tool 700 and implant 320.

For some applications, the proximity sensor comprises at least oneradiofrequency (RF) coil coupled to implant 320, and at least one RFcoil coupled to delivery tool 700. For example, the RF coil coupled totool 700 may transmit energy to the RF coil which is coupled to implant320. Typically, the RF receiving coil which is coupled to the implanthas a load modulation circuit which imposes changes in the transmissionsignal, which are detected by the transmitting coil coupled to tool 700.Thus, the RF coil coupled to tool 700, e.g., at a distal end of tool700, receives a baseline level of feedback from the RF coil coupled toimplant 320 when implant 320 is mounted onto tool 700. A difference inthe feedback from the RF coil coupled to the implant and received bytool 700 typically indicates proper separation of implant 320 from tool700. On the other hand, pulling back of tool 700 without a change (orwithout a sufficient change) in the feedback typically indicatesinsufficient detachment between implant 320 and tool 700.

For some applications, the proximity sensor comprises at least onemagnetic element coupled to implant 320 and at least one magneticelement coupled to the delivery tool 700. A sufficient change in themagnetic force between the two elements indicates sufficient detachment.

It is noted that the proximity sensor can be used in combination with,or in the absence of, optical fiber 420. The proximity sensor is used toindicate that delivery tool 700 is detached from the implant bygenerating a signal in response to relative motion (e.g., distancing)between delivery tool 700 and implant 320. For such applications, and ingeneral, implant 320 typically has a maximum length of 4 cm and/or amaximum diameter of 3 mm.

Reference is made to FIGS. 19 and 20, which are flow charts of steps fora method provided, in accordance with some applications of the presentinvention. For some applications, a travel path of implant 320 throughthe greater palatine canal is assessed by navigation system (NS), e.g.,using optical markers 500, 510 and 520 on tool 700. Additionally, atravel path of implant 320 is assessed by the optical fiber shapesensing system (OFSSS) based on shape changes of the optical fiberduring advancement to the SPG, as described herein. Typically it ispossible to indicate whether there is an error in the travel pathassessed using the navigation system if (a) the travel path detectedusing the optical fiber shape-sensing system matches a pre-operativelydetermined shape of the canal, typically obtained by CT-scan, and (b)the travel path assessed using the navigation system indicates that theneural stimulator has passed out of the canal. FIG. 20 is a flow chartshowing the above described steps for indicating whether there is anerror in the travel path assessed using the navigation system (NS), inaccordance with some applications of the present invention.

Alternatively or additionally, the scope of the present inventionincludes indicating whether there is an error in the travel pathassessed using at least one of the systems (i.e., NS and OFSSS) if (a)the travel path assessed using the navigation system matchespre-operative registration data of the optical marker, and (b) thetravel path detected using the optical fiber shape-sensing systemindicates that the neural stimulator has passed out of the canal. Incases in which an error is indicated, the navigation system is typicallyrecalibrated by performing registration of the optical markers. FIG. 19is a flow chart showing steps for indicating whether there is an errorin the travel path assessed using at least one of the systems (i.e., NSand OFSSS).

Reference is now made to FIG. 21. For some applications, optical fiber420 is distally advanced in the palatine canal without neural stimulatorimplant 320. For some such applications, delivery tool 700 comprises asteerable delivery device 760, e.g., a steerable trocar. As shown inFIG. 21, steerable delivery device 760 comprises axis 222 at a hinge ofsteerable delivery device 760, allowing steering of distal portion 762of device 760. Portion 764 of steerable delivery device 760 is typicallyflexible, facilitating advancement through the palatine canal based onthe steering of distal portion 762. Optical fiber 420 is typicallydistally advanced through the palatine canal using steerable deliverydevice 760 of tool 700.

A shape of the canal is assessed, e.g., mapped, using optical fibershape-sensing system 426, based on a shape of optical fiber 420 duringadvancement through the palatine canal. Typically, steerable deliverydevice 760 is navigated in the palatine canal based on the assessing ofthe shape of the palatine canal. Accordingly, use of optical fiber 420typically facilitates safe steering of delivery device 760 in thepalatine canal, avoiding injuring to the palatine canal. Steerabledelivery device 760 may be steered by deflection of a distal end ofsteerable delivery device 760.

Optical fiber 420 is then removed from the palatine canal andsubsequently to removal of fiber 420, neural stimulator implant 320 isdistally advanced using delivery tool 700, with or without deliverydevice 760, or using another delivery tool, through the palatine canal,and is implanted at a vicinity of the sphenopalatine ganglion (SPG) toapply electrical stimulation thereto. Typically, neural stimulatorimplant 320 is navigated through the palatine canal based on assessingof the shape of the palatine canal with optical fiber 420.

As described hereinabove, for some applications, a proximity sensor isconfigured to indicate that delivery tool 700 is detached from implant320 by generating a signal that varies in response to relative motion(e.g., distancing) between delivery tool 700 and implant 320.

For some applications, prior to advancement of neural stimulator implant320, delivery device 760 is advanced in the palatine canal together withfiber 420 and is used to prepare the palatine canal for subsequentadvancement of neural stimulator implant 320, e.g., by widening thepalatine canal. It is noted that preparation of the palatine canal withdelivery device 760 and fiber 420 in the absence of neural stimulatorimplant 320 avoids forces of tissue clearance during preparation of thecanal from being applied to neural stimulator implant 320. It is notedhowever, that for other applications as described for example in FIGS.15A-B, neural stimulator implant 320 is advanced with fiber 420 and thedelivery tool.

For some applications, for example, when a shape of the palatine canalis assessed by optical fiber 420 and/or by pre-operative CT as havingmany curves that would make advancing of neural stimulator implant 320therethrough difficult, neural stimulator implant 320 may be advancedout of the palatine canal through a naturally-occurring or asurgically-made hole in the canal. In such cases, neural stimulatorimplant 320 is advanced out of the palatine canal, and for example,parallel to the canal, through the maxillary sinus which is locatedlateral to the palatine canal, toward the sphenopalatine ganglion (SPG).

Reference is again made to FIGS. 14-21. It is noted that shape sensingof the palatine canal with fiber 420 as described herein is performed ona sensing length of 4-6 cm (e.g., 5 cm) of fiber 420, which is theapproximate length of the palatine canal. Thus, for example, the fiberBragg gratings for use for these applications are typically positioned2-5 mm apart.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

The invention claimed is:
 1. Apparatus for use with an optical fibershape-sensing system, the apparatus comprising: an optical fiber,optically couplable to the optical fiber shape-sensing system, andconfigured to change shape during advancement through a greater palatinecanal of a subject; a delivery tool configured to be removably coupledto the optical fiber and to distally advance the optical fiber throughthe greater palatine canal; and a neural stimulator implant, which is(a) shaped and sized to be delivered to a sphenopalatine ganglion (SPG)of the subject by the delivery tool, (b) configured to not be in contactwith the optical fiber during delivery of the neural stimulator implantby the delivery tool, and (c) configured to apply electrical stimulationto the SPG.
 2. The apparatus according to claim 1, wherein the neuralstimulator implant is not disposed within the delivery tool.
 3. Theapparatus according to claim 1, wherein the optical fiber has a sensinglength of 4-6 cm.
 4. The apparatus according to claim 3, wherein theoptical fiber has fiber Bragg gratings that are positioned 2-5 mm apartfrom each other.
 5. The apparatus according to claim 1, wherein theoptical fiber shape-sensing system includes optical fiber shape-sensingcircuitry and wherein the optical fiber is optically couplable to theoptical fiber shape-sensing circuitry.
 6. The apparatus according toclaim 1, wherein the neural stimulator has a proximal portion, a distalportion and a middle portion between the proximal and distal portions,and wherein the proximal portion is more rigid than the middle portion.7. The apparatus according to claim 6, wherein the distal portion ismore rigid than the middle portion.
 8. The apparatus according to claim1, wherein the optical fiber has fiber Bragg gratings.
 9. A methodcomprising: using a delivery tool, distally advancing, through a greaterpalatine canal of a subject, an optical fiber being configured to changeshape during advancement through the greater palatine canal; assessing ashape of the palatine canal using an optical fiber shape-sensing system,based on a shape of the optical fiber during advancement; removing theoptical fiber from the greater palatine canal; and subsequently toremoving the optical fiber, distally advancing through the greaterpalatine canal a neural stimulator that is configured to applyelectrical stimulation to a sphenopalatine ganglion (SPG) of thesubject.
 10. The method according to claim 9, wherein distally advancingthe neural stimulator comprises navigating the neural stimulator in thepalatine canal based on the assessing of the shape of the palatinecanal.
 11. The method according to claim 9, wherein using the deliverytool comprises navigating the delivery tool in the palatine canal basedon the assessing of the shape of the palatine canal.
 12. The methodaccording to claim 9, wherein assessing the shape of the palatine canalusing the optical fiber shape-sensing system, comprises mapping thepalatine canal based on a shape of the optical fiber during advancement.13. The method according to claim 9, further comprising implanting theneural stimulator in a vicinity of the SPG.
 14. The method according toclaim 9, wherein the optical fiber shape-sensing system includes opticalfiber shape-sensing circuitry and wherein assessing comprises assessinga shape of the palatine canal using the optical fiber shape-sensingcircuitry.
 15. The method according to claim 9, further comprising,using the delivery tool during the distal advancing thereof, wideningthe palatine canal in preparation for advancing of the neuralstimulator.
 16. Apparatus comprising: an optical fiber shape-sensingsystem; an optical fiber, optically couplable to the optical fibershape-sensing system, and configured to change shape during advancementthrough a greater palatine canal of a subject; a delivery toolconfigured to be removably coupled to the optical fiber and to distallyadvance the optical fiber through the greater palatine canal; and aneural stimulator implant, which is (a) shaped and sized to be deliveredto a sphenopalatine ganglion (SPG) of the subject by the delivery tool,(b) configured to not be in contact with the optical fiber duringdelivery of the neural stimulator implant by the delivery tool, and (c)configured to apply electrical stimulation to the SPG.
 17. The apparatusaccording to claim 16, wherein the optical fiber has a sensing length of4-6 cm.
 18. The apparatus according to claim 17, wherein the opticalfiber has fiber Bragg gratings that are positioned 2-5 mm apart fromeach other.
 19. The apparatus according to claim 16, wherein the opticalfiber shape-sensing system comprises optical fiber shape-sensingcircuitry and wherein the optical fiber is optically couplable to theoptical fiber shape-sensing circuitry.
 20. The apparatus according toclaim 16, wherein the neural stimulator has a proximal portion, a distalportion and a middle portion between the proximal and distal portions,and wherein the proximal portion is more rigid than the middle portion.